Avoid Distinct
Avoid Distinct :
We are using distinct in some queries to get required result set.
for instance,
SELECT DISTINCT(a.order_id) FROM order a, order_date d where a.order_id=d.order_id.
Here,
We are using order_date table in where clause.we are getting result set then pull out duplicates. It makes some delay.To optimize this query,we can use sub query .
SELECT a.order_id FROM order where a.order_id in (SELECT d.order_id from order_date d)
